For private homes and also local area networks (LAN) developments are going on to connect all kinds of devices together, as TV, personal computer, stereo systems, telephone etc. Several devices located in an area and belonging to a group of dedicated users, for example in the same apartment or in the same building, may be considered to be part of a so-called cluster. This may also include near-by-stations outside the respective building. Information exchange between the devices of the cluster and optionally between the cluster devices and stations of other near-by-clusters may be based on wireless RF communication. However, a combination of wireless and wire line RF communication may also be provided.
For the RF communication between the devices and/or the outside stations there will only be a limited number of RF channels available. Devices of a cluster, and/or optionally such of different clusters which communicate with each other, use one (or optionally more than one) channel by sharing a plurality of time and/or frequency slots. This normally causes no interference problems. The devices and the stations of the various clusters may use/reuse the RF channels available for communication under certain conditions (distance, interference level, etc.). Therefore, communication signals from devices in other clusters in most cases cause interference problems with respect to communication of the devices of the cluster considered. In situations of high communication traffic, interference may prevent a reuse of the same channel and, if no more channels are available, it blocks usage of a desired service.
The general concept of a mixed frequency and time division multiplex communication system is described in EP-A-0 853 400. For the disclosure of the invention it is therefore expressively referred to this document.
In order to avoid conflicting situations, before entering and using a preferred channel for communication each device separately performs a channel testing procedure. In the channel testing procedure, on the basis of communication parameters the preferred channel is tested whether it enables RF communication, preferably optimised communication over the preferred channel.